Descriptive Mineralogy - University of Colorado Boulder

Descriptive Mineralogy Native Elements: Pure elements that occur as minerals

Classification of the Minerals Non-Silicates

Native Elements Halides Sulfides Oxides

Hydroxides Carbonates Sulfates Phosphates

Silicates

Orthosilicates Sorosilicates

Cyclosilicates Chain Silicates Layer Silicates Tektosilicates

Native Elements Native Elements: Metals Fe, Co, Ni: Meteorites Platinum Group: (Ru, Rh, Pd, Os, Ir, Pt):

Mafic Igneous Rocks Coinage metals: Cu, Ag, Au Cu, Ag: Supergene Enrichments (Sulfide Oxidation) Au: Low Temperature Hydrothermal, Placer

Native Iron: Meteorites Native Iron: Meteorites Widmansttten Pattern

Iron-Nickel Phase Diagram Platinum Group Metals Ru, Rh, Pd, Os, Ir, Pt

Strongly siderophile elements Enriched in Fe meteorites Found in layered mafic intrusions Bushvelt Complex (South Africa) Stillwater Complex (Montana)

Skaergaard Complex (Greenland) Bushvelt: Layered Gabbroic Intrusion Bushvelt: Layered Gabbroic Intrusion

Skaergaard: Layered Gabbroic Intrusion Skaergaard: Layered Gabbroic Intrusion

Skaergaard: Layered Gabbroic Intrusion Native Elements: Cu, Ag, Au Cu and Ag: Supergene Enrichment Oxidation of Cu, Ag sulfides in unsaturated

zone Precipitation of metal, oxides and carbonates at water table Ag and Au: hydrothermal

Native metals and tellurides Au: placer oxidized hydrothermal

Supergene Copper Hydrothermal Silver Hydrothermal Gold

Hydrothermal Gold Native Elements: non metals Carbon:

Graphite: Metamorphic Rocks Diamond: Kimberlites Sulfur (+Se): Salt Domes (Sulfate reduction),

Volcanos (H2S oxidation) Tellurium (Te) Telluride oxidation Native Elements: Carbon

Graphite (Low Pressure) Metamorphosed Organic-rich sediments Diamond (High Pressure >100km) Kimberlites

Placers from kimberlites Native Elements: Diamond Native Elements: Diamond

Kimberley Mine 1875 Native Elements: Sulfur Fumaroles (Volcanic hydrothermal vents)

Oxidation of H2S Salt dome cap rocks Sulfate reduction by petroleum

Fumarole Sulfur: Nysseros In the caps of salt domes, gypsum (CaSO4 2H2O) is reduced to native sulfur

Native Elements

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